Reversing stroke retractor mechanism



Feb. 14, 1961 L. F. BLATT REVERSING STROKE RETRACTOR MECHANISM 5 Sheets-Sheet 1 Filed July 21, 1958 IN VEN TOR.

7' fiz A ORA/ rs ZELfllVD F BY m 7 l Feb. 14, 1961 L. F. BLATT REVERSING STROKE RETRACTOR MECHANISM 5 Sheets-Sheet 2 Filed July 21,. 1958 INVENTOR fi v 47- roe/vim" Feb. 14, 1961 F. 'BLATT REVERSING STROKE RETRACTOR MECHANISM 5 Sheets-Sheet 3 Filed July 21, 1958 llrllr IL Feb. 14, 1961 L. F. BLATT REVERSING STROKE RETRACTOR MECHANISM! 5 Sheets-Sheet 4 Filed July 21, 1958 IN VEN TOR.

47' 7' ORA i K5" Feb. 14, 1961 L. F. BLATT REVERSING STROKE RETRACTOR MECHANISM 5 Sheets-Sheet 5 Filed July 21, 1958 INVENTOR.

United States PatentO REVERSIN G STROKE RETRACT OR MECHANISM,

Leland F. Blatt, 790 Shoreham Road, Grosse Pointe Woods 36, Mich.

Filed July 21, 1958, Ser. No. 749,824

20 Claims. (Cl. 74110) The present invention relates to an improved reversible stroke mechanism for the handling of work in production equipment. A typical example of the application of the principle of the invention is in a retractor device by which work is presented for a punching or like operation and removed following the operation. This involves the gripping and rapid advance of a sheet metal plate or the like into a punch press, the withdrawal of the punched sheet and its release and deposit in a stack, as l8, single operating cycle. However, it is to be understood, as will appear from the description to follow, that the principles of the invention are not at all limited in respect to any such special application. The improved mechanism is to be broadly considered as one for performing a reversing stroke of any desired sort with speed and precision, and in a smooth, relatively shock-free manner.

It is an object of the invention to provide a high speed, flexible chain and sprocket type reversing mechanism for this purpose, featuring sets of driving and driven chains trained about sprockets of materially different diameter. These chains are operatively connected, respectively, to a driving instrumentality and to a driven instrumentality (such as a reversing stroke retractor carriage), in a way to effect a desired multiplication of speed of the latter for a given speed reversing operation of the driving chain.

Another object is to provide a reversing mechanism of this sort, in which the reversing driving instrumentality is simply and inexpensively provided in the form of a reversing air cylinder, and in which the reversing control for the cylinder is mechanically derived from the driving chain and its sprocket connection.

A still further object is to provide a speed multiplyin chain and sprocket driving arrangement in a reversing mechanism of the class described, in which cushioned means are present to maintain chain tension at all times in the driven or power output chain, regardless of the direction of its drive; and, moreover, to do this without shock as the direction of chain travel reverses.

More specifically, it is an object to provide a reversing stroke mechanism of this sort, in which the anti-shock, chain tensioning provisions take the form of a floating mount for the sprocket of the power output chain unit, which also affords a part of a floating mount for the reversing air cylinder. Thus the air cylinder has a plunger operatively connected to the smaller .sprocketed driving chain in a way to move the same in reverse directions in its endless path, as air pressure is reversibly applied to the cylinder. The reactive force sustaining the air cylinder is supplied through the iioatingly mounted sprocket to the power output chain; and the effect of force and reaction keeps propertension at all times in the power chain, with its stroke precisely accurate in either direction;

-A still further object is to provide precision automatic reversing arrangement of this sort in which a cushioned balance link unit is effective, as the power output chain and sprocket are thus employed, to cushion the force of the sprocket on the chain in reversing, as well as to maintain chain tension. i

The foregoing as well as other objects will become more apparent as tins description proceeds, especially when considered in connection with the accompanying drawings illustrating the invention, wherein:

Fig. 1 is a view in side elevation of the improved mechanism, being partially broken away and in vertical section along a line generally corresponding to line 1-1 of Fig. 2;

Fig. 2 is a top plan view of the mechanism, also partially broken away and in horizontal section, showing the arrangement of chain sets, supporting sprockets, air cylinder mount and cushioning means of the invention;

Fig. 3 is an end elevational view, partially broken away and in vertical section along line 3-3 of Fig. 1; and

Figs. 4 through 7 are, respectively, fragmentary views in vertical transverse section along lines 4-4, 5-5, 6--6 and 7-7 of Fig. 1.

Referring first, and in a general way, to Fig. l of the drawings, the improved reversing stroke mechanism 10 of the invention is shown as being equipped with a reversing carriage, generally designated 11, operating in a horizontal plane; and as applied to material handling and retracting equipment of the sort referred to above, this carriage 11 will have mounted thereto a suitable retractor head (not shown). Such head may be of a conventional type, operated pneumatically or hydraulically to seize a piece to be handled, present it to a punch press or like operating mechanism, withdraw it after such operation, and perform a repetition of such cycles. However, the invention does not concern itself particularly with these aspects, and it will therefore be considered that the carriage 11 will represent any desired sort of operated unit which is to be moved to and fro in a properly timed cycle at relatively high speed, yet smoothly and without undue shock as the direction of its movement reverses.

The component parts of the reversing mechanism 10 are mounted in and about a suitable rigid housing struc ture, generally designated 12. This structure may comprise a pair of suitably long channels 13 disposed upright in transversely spaced relation to one another and with their webs 14 upright and their respective top and bottom flanges 15, 16 facing one another, as shown in Fig. 3. Supplemental side plates 17 are welded along the outer sides of the channels 13, adjacent one end thereof for additional bearing rigidity, and the channel webs 14 are further provided with elongated apertures 18 affording access to certain further mounting provisions, as well as to accommodate longitudinal floating movement of certain components within the housing 12, as will be described.

Referring to Figs. 3 and 4, an elongated horizontal bed 21 is welded to and along the bottom flanges 16, of the channels 13, this bed having a central clearance opening 22 extending along and beneath the corresponding elongated central zone between adjacent edges of th channel flanges 16. These zones accommodate sprockets and an endless power chain, to be described. The bed is provided with elongated outer inclined ways 23, and the carriage 11 includes, in spaced positions along either side thereof, the pairs of anti-friction rollers 24, 25. Rollers 25 are on inclined axes and engage the respective Way surfaces 23 to suspend the carriage 11 in its reciprocating movement. Rollers 24 engage the bottom surfaces of the bed 21 directly beneath the ways 23. t

Further in respect to the structure of the housing 12, it includes a pair of endplates 27, 28, suitably secured across the opposite ends thereof, and above the end plate 28 a tension link assembly, generally designated 29, is welded together to move between the channels 13.

Assembly 29'includes a cross head 30, a welded part of assembly 29, above the end plate 28, and elongated straplike elements 31 Welded to cross head 30 at either side thereof and projecting forwardly thereof beneath the respective upper channel flanges 15. Each strap 31 is appropriately secured, as by welding (see Figs. 2, 4 and 7), to the cross head 30 adjacent channel web 14, and it projects forwardly, or to the left as viewed in Figs. 1 and 2, to theapproximate location of one of the openings 18 in the web. There the straps 31 have welded to them the upright bracket elements 32, exposed for access at openings 18, which are of appropriately thick and rugged cross section for the sprocket bearing function which they are intended to perform.

Just to the left of the brackets 32, as viewed in Figs. 1 and 2 (see also Fig. the channel webs 14 each have welded thereto a horizontally extending way or guide element 34, along which a plunger guide block 35 is adapted to reciprocate, in a way to be described.

To complete the housing structure 12, reference now being had to Figs. 1 and 7, a pair of horizontal roller ways 37 are welded along the inner surface of the channel Webs, directly above the bottom channel flanges 16, and,

, in vertically spaced relation above these ways, each channel has a furtherrestraining way and bearing element 38 of elongated character welded thereto. The members 38 lie directly beneath the bearing strap members 31 of the tension link'assembly 29, as appears in Figs. 4 and 7.

Referring to Fig. 3 of the drawings, a sprocket and spacer assembly 42 is rotatably mounted on a horizontal transverse shaft 43 adjacent one end of the housing 12. The shaft 43 may be fixed in the wallsof the housing constituted by the channel webs 14 and supplemental plates 17; and assembly 42 may comprise a central sprocket 44 rotatably borne by shaft 43, with suitable bushing means 45 interposed, and with like sprockets 46 of smaller diameter and number of teeth at either axial side of the sprocket 44. Sprockets 46 have hubs 47 which abut the sides of sprocket 44, and a bronze spacer 48 is positioned between one sprocket 46 and the adjacent housing channel 13. A further sprocket 50 is arranged on the opposite side of the assembly 42, with an appropriate spacer 51 between it and the adjacent housing wall. One or more bolts or studs 52 are disposed through the hubs of the respective sprockets 44, 46 and 50 to lock these members as a unit for rotation about shaft 43 as an axis. The sprocket 50 is a power take-off sprocket which, as illustrated in Figs. 1 and 2, is connected by a chain 54 with the sprocket on the shaft of a driven unit 55 mounted exteriorly of the adjacent end of housing 12. Thus,.in accordance with the invention, the unit 55 may be a suitable valve control unit, driven in synchronism with the reversing drive of the mechanism and employed, for example, in reversing the application of air'to an operating air cylinder of the unit, which is generally designated by the reference numeral 56.

A driven reversing or power chain 58 is trained about the central sprocket 44, which is' substantially larger in diameter than the sprockets 46, as shown in Fig. 3, Chain 58 is provided at. spaced links thereof with pairs of opposed anti-friction rollers 59 which, as the chain travels beneath the housing in engagement with sprocket 44, are guided by elongated ways 60 beneath .the elongated clearance opening 26 of the bed 21. At an appropriate point along its length the chain 58 is connected by a pair of mounting brackets 61 with an elongated member 62 of the carriage 11. I

' Thus, as power chain 53 is reversed in its movement by the provisions to be described, the carriage 11 has corresponding reciprocatory movement imparted thereto in the directions indicated by arrows in Fig. 1. The sprocket means for the other end of thepo'wer chain 58 are floatingly mounted, in accordance with the invention, by provisions hereinafter to be described. V v As shown in Figs. 1 and '6, the downwardly disposed bracket members 32 on the elongated side straps 31 of the housing structure provide a floating bearing support at 64 for a pair of sprockets 65 which are transversely spaced from one another and are longitudinally aligned with the respective smaller sprockets 46 journalled b-y shaft 43. As shown in Figs. 2 and 6, such bearing means is received for limited floating movement in the elongated housing apertures 18. Driving chains 67 are trained about the respective sets of sprockets 46, 65, and, as illustrated in Figs. 1 and 5, an actuating block or cross head 63 is clamped between transversely aligned links of the chains 67, at an appropriate point along the lower reach of the chains 67. To this end, a clamp element 69 is provided which, like the block 68, is recessed at 70 to receive and accommodate the chain links in question, being taken up by a screw 71 to hold the links firmly. Block 68 is provided with guide elements '72 on its opposite sides which are longitudinally recessed at 73 for sliding engagement with the respective guideways 34, mentioned above, on the inner sides of the housing channel webs 14. The air cylinder 56 is adapted to float longitudinally as supported by clevis and other means to be described, in the space between the channels of housing 12 and has an actuating plunger 75 extending therefrom, i.e., to the left as viewed in Figs. 1 and 2, which plunger is threadedly received in the actuating block or cross head 68, in centered relation between and above the lower reaches of the two actuating chains 67. Thus, as the plunger is reciprocated by air cylinder 56, corresponding movement is imparted to the cross head or block 68. As gripped by clamp 69 to the lower reach of the two chains 67, the latter are correspondingly moved reversibly in the horizontal sense. This motion is transmitted in increased amplitude, due to the different diameters of the sprockets 46 and 44, to the power chain 58, thence to the carriage 11, as described above.

Cylinder 56 is provided with suitable fittings '77, 78 for connecting its opposite ends to a source of reversing air, pressure, which may be considered the unit 55 referred to above, and it will be understood that plunger 75 carries an appropriate piston or head (not shown) within cylinder 56 to accomplish reversing strokes. The nature of such provisions will be evident to one skilled in the art, and they constitute no part of the present invention.

In order to attain the cushioned automatic take-up of the power chain 58, in the manner contemplated by the invention, the air cylinder, described as having a floating action within the housing, is provided with a pair of transversely spaced clevis members 8%), which are secured by bolts 31 to the adjacent end of air cylinder 56, and extend to the right thereof, as viewed in Figs. 1 and 2. C levis members 89 receive a shaft 82 in the eyes thereof, upon which shaft a sprocket 83 is rotatably mounted in longitudinal alignment with the other large sprocket 44. Sprocket 83 has the power chain 58 trained about it at this end of the mechanism, as shown in Figs. 1 and 2. A forked or clevis type compression link 85 is pivoted on the shaft 82 at either side of the respective clevis members 80, and outwardly of each link 85 there is an antifriction roller 86 supporting the shaft for rolling action upon one of the side roller Ways 37 of housing structure 12. I

' At their opposite ends the compression links 85 are pivotally mounted by pins saw the lower end of a balance link 89, which has a central fixed pivot at 9% on the adjacent housing bar 38. The upper end of each balance link 89 is'pivotally connected by means of a pin 92 to a pressure clevis 93, this pressure clevis having a rear stem 94 which is slidably guided by the frame of the tension link assembly 2?. A coil spring 95 Within each of two tubular housings 96 of this assembly, which housings are welded to the respective straps 31 of the latter, as appears in Figs. 2, 4 and 7, acts against the clevis (as showninlFig. 2) to urge thesame to theleft, as shown in 5. that figure. 'The opposite end of the spring abuts against a pressure plug 97 which is adjustably sustained by a set screw 98 threaded in the cross head 30, thus urging the latter and the straps 31 and bearing bracket elements 32 to the right, as viewed in Figs. 1 and 2.

The mechanism may be fixedly supported in any suitable manner adjacent the operating equipment which it is intended to serve. However, for this purpose, reference being had to Figs. 1, 3 and 4, the top flanges of the respective channels 13 may have a pair of elongated retainer and hold-down pieces 160 mounted thereon, with a dovetail type, elongated mounting base 191 therebetween. The base 101 may provide a split clamp head 102 to be received by a rigid cross arm 103. Thus, with the base 101 appropriately positioned on housing 12, the screws 104 may be taken up to hold it in place, and the clamp member 102 may be similarly taken upby tightening screws 105 to hold the housing in any desired position along the bar 103.

In the operation of the above mechanism, it is seen that upon application of pneumatic pressure to one of the fittings of air cylinder 56, for example, the fitting 78, plunger 75 will be thrust to the left, as viewed in Fig. l, forcing the guide or actuating block 35 on the lower reaches or" actuating chains 67 in the same direction, as the latter train around sprocket 46 and as power chain 58 trains around the coaxial left-hand, larger sprocket 44. Reaction is furnished by the thrust of the opposite large sprocket 83 against power chain 58, with the result that the balance link 89 tends to be swung clockwise, as viewed in Fig. 1, about its fixed pivot W, i.e., from the dotted line to the solid line position, against the cushioning action of the springs 95. Tension in chains 58 and 67 is maintained by springs 95, the force of the latter being applied to urge sprockets 65 to the right through the agency of the tension link assembly 29 against which the springs Work. When pressure is applied to the other fitting 77 of air cylinder 56, the same reactive efiort exists, and the power chain 58 is kept under fully controlled tension at all times, during and upon reversal of its motion in either direction, and being well cushioned against shock at the times of reversal.

Stated otherwise, as viewed in Fig. 1, and assuming that the carriage 11 has been driven by power chain 58, to the extreme left of its stroke, the pull of the bottom reach of chain 58 on the right-hand, floatingly mounted sprocket 83 tends to shift the latter to the left, with a connection through the agency of clevis links 85 on sprocket shaft 82 urging balance links clockwise about their pivot at 90 against the resistance of springs 95. Halting of power chain 58 and carriage 11 at the left hand stroke limit is thus resiliently cushioned by the springs. On the other hand, when the carriage reaches the right hand limit of its stroke, the pull of the top reach of chain 58 on sprocket 83 has the same effect; the balance links 89 are urged clockwise against the resilient cushion of springs 95, and the carriage 11 is correspondingly cushioned in coming to a halt.

The mechanism 10 is very rugged and inexpensive in construction, is compact,'and is readily applied to a variety of types of operating equipment requiring a rapid, shockproof reversing stroke of the precise character that the floating chain tensioning action of the mechanism insures.

What I claim as my invention is:

1. A mechanism of the class described, comprising a first endless member, a pair of spaced rotative members of given diameter about which said endless member is trained, a further pair of spaced rotative members, one of which is drivingly connected to and coaXially rotatable with a member of the first pair, said further pair of members being of substantially difierent diameter than said first pair, a second endless member trained about said further pair of rotative members, and an operating device provided with a reciprocatory member drivingly connected to a reach of one of said endless members to correspondingly reciprocate the latter and thereby, through 6 the agency of the drivingly connected rotative members, to reciprocate the other endless member at a substantially different speed. i r

2. A mechanism of the class described, comprising a driven member mounted for reversing stroke travel, a first endless power output member operatively connected to said member to move linearly therewith and actuate the same for its travel, a pair of spaced rotative members of given diameter about which said endless member is trained and by which it is driven, a further pair of spaced rotative members, one of which is drivingly connected to and coaxially rotatable with a member of the first pair, said further pair of members being of substantially difierent diameter than said first pair, a second endless driving member trained about said further pair of rotative members, and an operating device provided with a reciprocatory member drivingly connected to a reach of one of said endless members to correspondingly reciprocate the latter and thereby, through the agency of the drivingly connected rotative members, to reciprocate the other endless member at a substantially different speed.

3. A mechanism of the class described, comprising a driven member mounted for reversing stroke travel, a first endless power output member operatively connected to said member to move linearly therewith and actuate the same for its travel, a pair of spaced rotative members of relatively large diameter about which said endless member is trained and by which it is driven, a further pair of spaced rotative members, one of which is drivingly connected to and coaxially rotatable with a member of the first pair, said further pair of members being of substantially smaller diameter than said first pair, a second endless driving member trained about said further pair of rotative members, and an operating device provided with a reciprocatory member drivingly connected to a reach of said second endless member to correspondingly reciprocate the latter and thereby, through the agency of the drivingly connected rotative members, to reciprocate said first endless member at a substantially greater speed.

4. A reciprocatory stroke mechanism comprising an endless member trained about a pair of spaced rotative members and having means to drivingly connect a reach thereof with an element reversibly operated thereby, means including a member coaxially oscillatable with one of said rotative members, but at a substantially different linear speed in rotation, to reversibly drive the latter, a device drivingly connected to said oscillatable member to reversibly operate the same at said linear speed, with resultant linear reversing movement of said reach and element at a different speed, and means actuated by operation of said device to thrust the other rotative member of said first named pair in directions respectively opposite of and the same as the direction of linear motion of said reach.

5, A reciprocatory stroke mechanism comprising an endless chain trained about a pair of spaced sprockets and having means to drivingly connect a reach thereof with an element reversibly operatedthereby, means including a member coaxially oscillatable with one of said sprockets, but at a substantially less linear speed in rotation, to reversibly drive the latter, a device drivingly connected to said oscillatable member to reversibly operate the same at said linear speed, with resultant linear reversing movement of said reach and element at a greater speed, and means actuated by operation of said device to thrust the other sprocket of said first named pair in directions respectively opposite of and the same as the direction of linear motion of said reach.

6. A cushioned reciprocatory stroke mechanism comprising an endless member trained about a pair of spaced rotative members and having means to drivingly connect a reach thereof with an element reversibly operated thereby, means including a member coaxially oscillatable with one of said rotative members, but at a substantially less linear speed in rotation, to reversibly drive the latter, a fluid pressure device drivingly connected to said oscillatable member to reversibly operate the same at said linear speed, with resultant linear reversing movement of said reach and element at a greater speed, and resiliently biased means actuated by pressurized operation of said fluid pressure device to resiliently thrust the other rotative member of said first named pair in directions respectively opposite of and the same as the direction of linear motion of said reach.

7. A cushioned reciprocatory stroke mechanism comprising an endless member trained about a pair of spaced rotative members and having means to drivingly connect a reach thereof with an element reversibly operated therebyymeans including a member coaxially oscillatable with one of said .rotative members to reversibly drive the latter, a fluid pressure device drivingly connected to said oscillatable member to reversibly operate the same, with resultant linear reversing movement of said reach and element, and resiliently biased means actuated by pressurized operation of said fluid pressure device to resiliently thrust the other rotative member of said first named pair in directions respectively opposite of and the same as the direction of linear motion of said reach.

8. A cushioned reciprocatory stroke mechanism comprising an endless member trained about a pair of spaced rotative members and having means to drivingly connect a reach thereof with an element reversibly operated thereby, means including a member coaxially oscillatable with one of said rotative members to reversibly drive the latter, a fluid pressure device drivingly connected to said oscillatable member to reversibly operate the same, with resultant linear reversing movement of said reach and element, and resiliently biased means actuated by pressurized operation of said fluid pressure device to resiliently thrust the other rotative member of said first named pair in directions respectively opposite of and the same as the direction of linear motion of said reach, said other of said rotative members being mounted for floating movement under said thrust and said fluid pressure device comprising coacting, fioatingly mounted plunger and cylinder members, one operatively connected to said oscillatable member to drive the same and the other operatively connected to said other rotative member to exert directand reactive forces thereon in opposite directions.

9. A cushioned reciprocatory stroke mechanism comprising an endless member trained about a pair of spaced rotative members and having means to drivingly connect .a reach thereof with an element reversibly operated thereby, means including a member coaxially osciilatable with one of said rotative members to reversibly drive the latter, a fluid pressure device drivingly connected to said oscillatable member to reversibly operate the same, with resultant linear reversing movement of said reach and element, and resiliently biased means actuated by pressurized operation" of said fluid pressure device to resiliently thrust the other rotative member of said first named pair in directions respectively opposite of and the same as the direction of linear motion of said reach, said other of said rotative members being mounted for floating movement under said thrust and said fluid presment transverse ofits, axis, means to drivingly connect a reach of said chain with a member reversibly operated thereby, an oscillatory member coaxially rotatable with the other of said sprockets to reversibly drive the latter, a fluidtpressure device drivingly connected to said oscillatory member to reversibly rotate the same, and means including a resilient device acting between said sprockets and effective upon pressurization of said fluid pressure device to thrust said sprockets apart relative to one another and maintain tension on said chain. I

11. A cushioned reciprocatory stroke mechanism comprising an endless chain trained about spaced sprockets, one of which has means mounting the same for movement transverse of its axis, means to drivingly connect a reach of said chain with a member reversibly operated thereby, an oscillatory sprocket member coaxially rotatable with the other of said sprockets to reversibly drive the latter, a further endless chain drivingly engaging said oscillatory sprocket member, a fluid pressure device drivingly connected to said further chain to reversibly drive the same, and means including a resilient device acting between said sprockets and efective upon pressurization or said fluid pressure device to thrust said first named sprockets apart relative to one another and maintain tension on said first named chain.

12. A cushioned reciprocatory stroke mechanism comprising an endless chain trained about spaced sprockets, one of which has means mounting the same for movement transverse of its axis, means to drivingly connect a reachof said chain with a member reversibly operated thereby, an oscillatory sprocket member coaxially rotatable with the other of said sprockets to reversibly drive the latter, a further endless chain drivingly engaging said oscillatory sprocket member, a fluid pressure device drivingly connected to said further chain to reversibly drive the same, and means including a resilient device acting between said'sprockets and effective upon pressurization of said fluid pressure device to thrust said first named'sprockets apart relative to one another and maintain tension on said first named chain, said fluid pressure device comprising coacting, floatingly mounted plunger and cylinder members, one drivingly connected to said further chain and the other operatively connected to said movably mounted sprocket, thereby to exert direct and reactive forces in opposite directions thereon.

13. A cushioned reciprocatory stroke mechanism comprising an endless chain trained about spaced sprockets, one of which has means mounting the same for movement transverse of its axis, means to drivingly connect a reach of said chain with a member reversibly operated thereby, an oscillatory sprocket member coaxially rotata-ble with the other of said sprockets to reversibly drive the latter, a further endless chain drivingly engaging'said oscillatory sprocket member, a fluid pressure device drivingly connectedito said further chain to reversibly drive the same, and means including a resilient device acting between said sprockets and effective upon pressurization of said fluidpressure device to thrust said first named sprockets apart relative to one another and maintain tension on said first named chain, said fluid pressure device comprising coacting, floatingly mounted plunger and cylinder members, one drivingly connected to said further chain and the other operatively connected to said movably mounted sprocket, thereby to exert direct and reactive "forces in opposite directions thereon, said last named means including a pivoted link guiding said fluid pressure device and transversely movable sprocket for floating movement, and a cushion device opposing said link in said movement.

14. A mechanism of the class described,'comprising a carriage mounted for reversing stroke travel, a first endless power chain operatively connected to said carriage to actuate the same for its travel,-a pair of spaced sprockets about which said power chain is trained and by which it is driven, a further pair of spaced sprockets, one of which is fixed to and coaxially rotatable with one of the sprockets of the first pair, each sprocket pair including one mounted for floating movement transversely of its axis, a second endless driving chain trained about said further pair of sprockets, means connected directly to a reach of said second chain and driving said coaxial sprockets to oscillate in unison, anda resilient device acting on said respective floating sprockets in a manner to maintain tension on said respective chains.

15. A mechanism of the class described, comprising a carriage mounted for reversing stroke travel, a first endless power chain operatively connected to said carriage to actuate the same for its travel, a pair of spaced sprockets about which said power chain is trained and by which it is driven, a further pair of spaced sprockets, one of which is fixed to and coaxially rotatable with one of the sprockets of the first pair, each sprocket pair including one mounted for floating movement transversely of its axis, a second endless driving chain trained about said further pair of sprockets, and means driving said coaxial sprockets to oscillate in unison, said last named means comprising a fluid pressure operated reversing device having relatively movable elements, said device being mounted for floating movement, means drivingly connecting one of said elements to a reach of said second chain to reciprocate the latter, means operatively connecting the other element of said device to one of said floating sprockets to floatingly mount the same, and a resilient device acting on said respective floating sprockets in a manner to maintain tension on said respective chains.

16. A mechanism of the class described, comprising a carriage mounted for reversing stroke travel, a first endless power chain operatively connected to said carriage to actuate the same for its travel, a pair of spaced sprockets about which said power chain is trained and by which it is driven, a further pair of spaced sprockets, one of which is fixed to and coaxially rotatable with one of the sprockets of the first pair, each sprocket pair including one mounted for floating movement transversely of its axis, a second endless driving chain trained about said further pair of sprockets, and means driving said coaxial sprockets to oscillate in unison, said last named means comprising a fluid pressure operated reversing device having relatively movable elements, said device being mounted for floating movement, means drivingly connecting one of said elements to a reach of said second chain to reciprocate the latter, means operatively connecting the other element of said device to one of said floating sprockets to floatingly mount the same, and a resilient cushion device acting on said respective floating sprockets to maintain tension on said respective chains, including a pivoted and resiliently biased member guiding said fluid pressure device and last named floating sprocket for said floating movement.

17. A mechanism of the class described, comprising a carriage mounted for reversing stroke travel, a first endless power chain operatively connected to said carriage to actuate the same for its travel, a pair of spaced sprockets of relatively large diameter about which said power chain is trained and by which it is driven, a further pair of spaced sprockets, one of which is fixed to and coaxially rotatable with one of the sprockets of the first pair, said further pair of sprockets being of substantially smaller diameter than said first pair, each sprocket pair including one mounted for floating movement transversely of its axis, a second endless driving chain trained about said further sprockets, and means driving said coaxial sprockets to oscillate in unison, said last named means comprising a fluid pressure operated reversing device having relatively movable elements, said device being mounted for floating movement, means drivingly connecting one of said elements to a reach of said second chain to reciprocate the latter, means operatively connecting the other element of said device to one of said floating sprockets to floatingly mount the same, including a pivoted and resiliently biased member guiding said fluid pressure device and last named floating sprocket for said floating movement.

18. A mechanism of the class described, comprising a first endless member, a pair of spaced rotative members of given diameter about which said endless member is trained, a further pair of spaced rotative members, one of which is drivingly connected to and coaxially rotatable with a member of the first pair, said further pair of members being of substantially different diameter than said first pair, each pair including a member mounted for movement transversely of its axis relative to the other member of the pair, a second endless member trained about said further pair of rotative members, an operating device drivingly connected directly to a reach of one of said endless members to reciprocate the latter and thereby, through the agency of the drivingly connected rotative members, to reciprocate the other endless member at a substantially difierent speed, and resilient means acting on the respective movably mounted rotative members in a manner to maintain tension on said respective endless members.

19. A mechanism of the class described, comprising a first endless member, a pair of spaced rotative members about which said endless member is trained, a further pair of spaced rotative members, one of which is drivingly connected to and coaxially rotatable with a member of the first pair, each pair including a member mounted for movement transversely of its axis relative to the other member of the pair, a second endlessmember trained about said further pair of rotative members, an operating device drivingly connected. to a reach of one of said endless members to reciprocate the latter and thereby, through the agency of the drivingly connected rotative members, to reciprocate the other endless member, and resilient means acting on the respective movably mounted rotating members in a manner to maintain tension on said respective endless members.

20. A mechanism of the class described, comprising a first endless member, a pair of spaced rotative members about which said endless members is trained, a further pair of spaced rotative members, one of which is drivingly connected to and coaxially rotatable with a member of the first pair, each pair including a member mounted for movement transversely of its axis relative to the other member of the pair, a second endless member trained about said further pair of rotative members, an operating device drivingly connected directly to a reach of one of said endless members to reciprocate the latter and thereby, through the agency of the drivingly connected rotative members, to reciprocate the other endless member, and means acting resiliently on the respective movably mounted members, as connected through a reach of one of said endless members to said operating device, to maintain tension on said respective endless members and to cushion the action of said operating device.

References Cited in the file of this patent UNITED STATES PATENTS 497,706 Chase et a1. May 16, 1893 ,341 Waters Sept. 29, 1925 77 Morse June 27, 1933 ,035 Deak-in Dec. 6, 1949 3. 22 Armstrong Sept. 22, 1953 

